multilocular cystic renal cell carcinoma with osseous ... - Urology

CASE REPORT

MULTILOCULAR CYSTIC RENAL CELL CARCINOMA WITH OSSEOUS METAPLASIA IN A 25-YEAR-OLD WOMAN TAMMY L. BLOOM, CHRISTINE L. GRAY SEARS, TODD R. WILLIAMS, RON L. LINFESTY, CHRISTOPHER L. AMLING

AND

ABSTRACT Multilocular cystic renal cell carcinoma, clear cell type, accounts for less than 1% of all renal tumors. It is characterized by variably sized, noncommunicating cysts separated by irregular, thick, and fibrous septa covered with clear cells microscopically. We report a case of a markedly calcified multilocular renal cell carcinoma, clear cell type, with diffuse osseous metaplasia. UROLOGY 61: 462ix–462xi, 2003. © 2003, Elsevier Science Inc.

A

25-year-old, otherwise healthy, woman presented to her primary care physician with 2 weeks of epigastric pain, nausea, and malaise. She had no other symptoms. The patient had no travel history outside the United States. The physical examination did not reveal an abdominal mass. The complete blood count and differential were normal, with the exception of eosinophilia (16.9%, normal 0% to 6%). The serum creatinine was 0.9 mg/dL (normal 0.5 to 1.5), and liver function tests were normal. Plain abdominal radiography (Fig. 1) demonstrated a calcified right upper quadrant mass measuring 11.5 ⫻ 8 cm. She also underwent computed tomography (CT) scanning (Fig. 2), which confirmed the location of the mass to the right kidney. Peripheral calcification, as well as internal enhancement with contrast, was evident, meeting the criteria for a Bosniak category IV cyst. The preoperative tuberculin skin test and serum echinococcal antibody titers were normal. The patient underwent radical nephrectomy without complications. The pathologic evaluation demonstrated a 10.5-cm multilocular cystic renal The Chief, Bureau of Medicine and Surgery, Navy Department, Washington, D.C., Clinical Investigation Program, sponsored this report as required by NSHSBETHINST 6000-41A. The views expressed in this article are those of the authors and do not reflect the official policy of the Department of the Navy, Department of Defense, or United States Government. From the Departments of Urology, Radiology, and Pathology, Naval Medical Center San Diego, San Diego, California Address for correspondence: Tammy Bloom, M.D., LCDR, MC, USNR, Department of Urology, Naval Medical Center San Diego, 384000 Bob Wilson Drive, Suite 200, San Diego, CA 92134-5000 Submitted: April 23, 2002, accepted (with revisions): September 6, 2002 © 2003, ELSEVIER SCIENCE INC. ALL RIGHTS RESERVED

FIGURE 1. Plain abdominal film demonstrating calcified right upper quadrant mass.

cell carcinoma, clear cell type, Furhman grade 2, with extension through the renal capsule but not through Gerota’s fascia (T3NxMx). This tumor demonstrated diffuse heterotopic bone formation or osseous metaplasia (Fig. 3). 0090-4295/03/$30.00 doi:10.1016/S0090-4295(02)02145-3 462ix

FIGURE 3. Photomicrograph of osseous metaplasia. FIGURE 2. (A) Contrast and (B) noncontrast CT scans demonstrating calcified renal mass.

COMMENT Daniel et al.1 studied 560 renal adenocarcinomas and 1946 renal cysts, of which 58 (10.3%) and 39 (2.3%) contained calcium, respectively. In the vast majority, the calcifications were mottled or punctate.1 CT now demonstrates calcium in up to 31% of renal cell carcinomas, with an increasing incidence of calcifications noted with increasing size, as noted by Zagoria et al.2 Renal cysts are commonly encountered as incidental findings on CT. Bosniak3 proposed a classification system based on specific CT findings to separate cystic renal lesions into surgical and nonsurgical lesions. Category I lesions are recognized as simple cortical cysts showing homogeneity, water content, and a sharp interface with the surrounding parenchyma. Category II lesions are minimally complicated, with one or two (less than 1-mm-thick) septations or fine calcifications in the walls or septa and hyperdense cysts that have homogeneous high attenuation and features of a category I cyst. Category IIF lesions have minimal complexity that need follow-up owing to some suspicious features and do not meet category II criteria perfectly. Category III lesions show wall thickening, nodularity, and thick, irregular calcifications 462x

or are multilocular with enhancing septa. Category IV lesions are clearly solid lesions with nonuniform or enhancing walls, nodules, or solid components that enhance by at least 10 Hounsfield units.4 Curry et al.4 assessed the practical usefulness of the Bosniak classification system for separating surgical from nonsurgical cystic renal masses by analyzing 116 renal cystic lesions on properly performed renal CT scans. A properly performed renal-dedicated CT technique is preferably performed on a helical CT with both unenhanced and contrast-enhanced thin-section scans, with collimation ideally at less than 5 mm. Fifteen resected category I and II lesions were correctly identified by CT criteria as benign on the subsequent pathologic evaluation. All 18 category IV lesions and 29 (59%) of the category III lesions were malignant. Their results support the use of the Bosniak classification system in separating surgical lesions from those that can be safely followed up by CT. Multilocular cystic renal cell carcinoma, clear cell type, accounts for less than 1% of all renal tumors. It is characterized by variably sized, noncommunicating cysts separated by irregular, thick, and fibrous septa covered with clear cells microscopically. The prognosis for multilocular cystic renal cell carcinoma is excellent. Koga et al.5 reported a 5 and 10-year disease-specific survival rate UROLOGY 61 (2), 2003

of 100% and 100%, respectively, with no recurrence or metastasis in 9 patients at a mean follow-up of 65 months. Corica et al.6 reported 22 (92%) of 24 patients had no evidence of recurrence at 5 years, with 2 patients dying of intercurrent disease. Calcifications have been reported in renal cell carcinoma, cystic renal disease, abscess, echinococcal disease, schistosomiasis, tuberculosis, xanthogranulomatous pyelonephritis, arteriovenous malformations, and hematoma. Such extensive calcification with osseous metaplasia and the young age of our patient have not been reported in association with multilocular cystic renal cell carcinoma.

UROLOGY 61 (2), 2003

REFERENCES 1. Daniel WW Jr, Berry CC, Mishkin MM, et al: Calcified renal masses: a review of ten years experience at the Mayo Clinic. Radiology 103: 503–508, 1972. 2. Zagoria RJ, Wolfman NT, Karstaedt N, et al: CT features of renal cell carcinoma with emphasis on relation to tumor size. Invest Radiol 25: 261–266, 1990. 3. Bosniak MA: The current radiological approach to renal cysts. Radiology 158: 1–10, 1986. 4. Curry NS, Cochran ST, and Bissada NK: Cystic renal masses: accurate Bosniak classification requires adequate renal CT. AJR Am J Roentgenol 175: 339 –342, 2000. 5. Koga S, Nishikido M, Hayashi T, et al: Outcome of surgery in cystic renal cell carcinoma. Urology 56: 67–70, 2000. 6. Corica FA, Iczkowski KA, Cheng L, et al: Cystic renal cell carcinoma is cured by resection: a study of 24 cases with long-term follow-up. J Urol 161: 408 –411, 1999.

462xi